Data transmission systems
Intelligence is conveyed in a PCM bit stream form with alternate bits being
inverted. Additional information is conveyed by violations of the
alternate bit rule so that two successive bits have the same polarity.
Prior to being coupled to the alternate mark inversion coder a
pseudo-random bit stream is mixed by binary addition without carry to the
intelligence bit stream to maintain low DC level in the transmitted mixed
bit stream and to maintain bit transitions relatively high.
Weir; Donald A. (Goff's Oak, EN), Usher; Eric S. (Ware, EN), Howells; George A. (Bishops Stortford, EN) |
International Standard Electric Corporation
October 8, 1976|